A/N: A little different than my normal style, but definitely fun.

When Finn was 11, his mother moved them into a small house that had a large tree house in the backyard. To Finn, the tree house was massive, the kind of tree house every boy dreamed of. And the new house was neighboring a castle! Or at least… that's what it looked like to him. It was really just a large two story house, white with pink shutters, but inside it lived a princess with pink hair and a pretty smile. Finn took to calling her Princess Bubblegum of Candy Kingdom, but his mother told him her name was Bonnibel, she was nineteen, and he needed to quit pestering the poor girl. Finn wasn't much for listening and the princess told his mother that she didn't mind his company at all; she enjoyed the break from her constant college studies. She even said to Finn once, "I don't mind being called a princess. It sort of reminds me of someone I miss…" And then she looked thoughtful for a moment, and somewhat sad, before returning right back to her normal cheery self.

The Princess lived alone in her castle, the King and Queen having passed away two years ago, and while Finn didn't really understand exactly where people went when they "passed," he knew that it meant that the Princess was alone and needed protection. What she needed was a knight! He volunteered himself, his dog, Jake, and his trusty sword-stick.

His rescue attempts and daring feats of a heroic nature often earned him forehead kisses of gratitude or small peppermint candies, and always earned at least a pretty smile. His chest always felt fuzzy and warm around her and her sugary smiles. Jake regularly teased him about it.

Finn was usually the only one who could hear Jake talk, but sometimes, when the Princess was joining them for an adventure, she said she could hear him too. When he told her that people claimed that he had an over-active imagination and too much energy, she replied, "Psh. No way. Your brain is filled with awesome. I wish I could dream the way you do." To Finn, she was perfection, even if she did get that far-off gaze sometimes when she looked at his tree house.

One evening, after six months of adventures in their new house and Bubblegum's back yard, Finn and Jake climbed into the tree house after watching a particularly scary vampire movie, where they stumbled upon a dark visitor. She sat on the hard wooden floor, hands draped over knees, staring out the window that faced Candy Kingdom. Her hair was a massive black shadow that moved with the breeze as though it was alive. Finn was scared, convinced that she was just like the vampire from the movie. While cowering behind him, Jake barked a warning.

Startled, the girl snapped her head towards them and smiled after a moment, the moonlight casting an eerie shadow across her pale skin. Finn was convinced he saw fangs, and behind him, whimpering, Jake agreed. His legs shook involuntarily as he tried to stand fast.

She looked amused and leaned closer to them, a mischievous glint to her eyes. "Boo!" she yelled suddenly, cackling as they tripped backwards over each other in their attempt to escape. Jake tried to run, but Finn thought of the vampire getting to the Princess and refused to budge; he held the scruff of fur between Jake's shoulders firmly, keeping him close. In the other hand, he clutched his stick-sword. He demanded to know who she was.

"Marceline," she replied casually, twisting one hand to the side for mild emphasis.

Jake wanted to know if she was a vampire, so Finn asked.

She stood slowly, her figure now blocking the moonlight streaming in from the window. Finn could no longer discern her features in the shadows, but he knew he could see two red orbs glowing where her eyes should be. The mass of her hair flowed behind her, shifting, shaping, and blending into the darkness. "Vampire?" She asked, as if the very thought was absurd. Finn almost breathed a sigh of relief until she continued, "Kid, I'm the Vampire Queen." Jake whimpered. She sat herself down again with a theatrical sigh. "Don't worry," she said, resettling into the lounged state they had discovered her in. "I drink blood, yeah, but I drink shades of red too… and I'm already full for the night. I won't hurt you." When Finn didn't budge, she added, "Promise."

Jake wasn't happy about it, but Finn decided to trust the Vampire Queen… for now. Marceline entertained them with grand stories about her travels around the world, some of which that were hardly believable, but had them laughing and offering "ooo"s and "aaa"s. When he finally remembered to, Finn asked what brought Marceline to their tree house. The Vampire Queen looked towards the Candy Kingdom through the window in the same way the Princess would look towards the tree house sometimes. With a softer voice, not the boisterous tone she'd used for her tales, she told Finn that his new house was her old house. His tree house had once been hers.

Finn was excited to ask if she and the Princess were friends, then maybe, he sure hoped, they could all adventure together, but Marceline's reply was a cheerless, "Not anymore," as she gazed back towards the Candy Kingdom. It seemed as though Marceline could tell Finn's heart sank. She whapped him in the shoulder with a soft fist and told him that she would definitely join Finn, Jake, and the Princess on an adventure someday soon. It wasn't long after that that Finn's mother called him in for the night. Marceline placed a finger over her lips and shooed him out of the tree house. She was nowhere to be seen when he glanced back over his shoulder.

Marceline came to visit a couple more times in the next few nights, only after dark, which solidified Jake's fears that she really was the Vampire Queen. She told them stories of her childhood with Princess Bubblegum, and how, interestingly enough, Marceline had called her a princess too. She even helped them play pranks on the grouchy, old man next door and laughed hard when Finn told her he'd named the old neighbor "Ice King". Simon, she told them, was his real name, but Ice King worked just fine too. To Finn, she was the coolest, even if on both nights, before she disappeared into the darkness, Finn could see her thoughtful glance directed at Bubblegum's castle.

Weeks passed, then, without a trace of the Vampire Queen and the Princess was very busy with her studies; "Dangerous experiments!" is what she called them. Finn suspected it was just the normal, boring homework she was always doing, and so he and Jake continued on their adventures alone. On a mostly quiet evening with the sun hanging low in the sky, the boys were resting in the tree house after an exceptionally exhausting wrestling bout. A ruckus outside brought both pairs of their curious eyes to the window that overlooked Candy Kingdom. They peeked just in time to see Bubblegum slap Marceline right across the cheek. The Vampire Queen's eyes were downcast, her head still turned to the side from Bubblegum's blow. Finn knew what was coming next, he was certain. Marceline, the mysteriously awesome Vampire Queen wouldn't take a challenge like that lightly, no way. Not even from a princess.

Finn's heart sank then, when he realized he was not there to protect his princess from the Queen's revenge. Before Finn could move, before he could even take his eyes away from the scene before him, Marceline reached out for Bubblegum's hand, the one that had struck her, the one that was still shaking with anger. He couldn't hear what they said, but he could see that tears ran down the Princess' cheeks. Marceline rubbed her thumb across the knuckles on Bubblegum's captured hand as she dabbed at Bubblegum's tears with the sleeve of her plaid shirt. Finn thought Marceline looked sorry and felt his heart hurt for both of them. He wished he could hear what they talked about. Jake said it was a love confession. Finn thought that love was gross, too sappy, and shoved the dog away from the window in disbelief. But when the Princess threw her arms around the Vampire Queen's neck and they hugged so tightly and for so long, Finn felt his face heat up with embarrassment. Maybe Jake was right after all. As the girls broke their hold on each other and leaned back to look one another in the eye, a smile was on the Princess' face that Finn had never seen before, a happiness she'd never shown him. Just when they leaned in, nose to nose, he turned away quickly, sliding his back down the wall, his face hot red and his heart pounding in his ears. Jake was right. Very right. Even if he thought love was gross, Finn couldn't help but feel a little bit of jealousy twist in his heart. He didn't look back through the window for the rest of the night.

Soon, as promised, Marceline began to adventure with Finn, Jake, and Bubblegum. Finn enjoyed their adventures more than ever, but didn't shake the jealous feelings he had when he saw them hold hands or lean in close to whisper to one another…

At least not until a girl with hair made of fire moved in across the street.

A/N: Thanks for reading! Hope you liked it!